Objective: To investigate the diagnostic value of intravoxel incoherence imaging (IVIM) for placenta accreta spectrum (PAS) and topography of placental invasion. Methods: Retrospectively collected 113 patients who underwent MRI examination (including IVIM sequence) and given birth in our center. Patients were divided into placental implantation group (PAS) (n=59) and non-implantation group(n=54) according to surgical records and pathological results. 15 cases of the non-implantation group who had both S1 and S2 areas were selected and divided into S1 area of non-implantation group(N-S1) and S2 area of non-implantation group (N-S2) based on peritoneal reflection; For the cases (n=22) implanted in both S1 and S2 areas, the implantation sites were divided into S1 area of PAS group (PSA-S1) and S2 area of PAS group based on peritoneal reflection. The perfusion fraction (f), perfusion diffusion coefficient (D*) and standard diffusion coefficient (D) were calculated to compare the differences in perfusion results among the groups and analyze the diagnostic value of the parameters. Results: The f value of PAS group was higher than that of non-implantation placenta group (f PAS group=31.35(7.56) vs f non-implantation placenta group=28.76(4.91), P =0.011); The f value of PAS-S2 was higher than PAS-S1 (fPAS-S2 =35.62±6.28 vs fPAS-S1 =30.77±6.41，P=0.023). Conclusion: The IVIM parameter f-value can be utilized to quantitatively evaluate the placenta accreta's hyper-perfusion condition, and f-value may be used in assisting the diagnosis of placenta accreta spectrum (PAS) and topography of placental invasion.